E.E. Knight, a self-described “pulp writer,” has compiled a list of blunders made by beginning authors. Obviously, some of these are a matter of taste (Ray Bradbury has made a career out of #2), but they’re worth a look if you’re trying to get your fiction published.
Strange days. Stranger names: I get sf/fantasy stories about orc-tribes where there’s Bolk, Gurg, and Fred. Which would be funny, I suppose, if it wasn’t a straight-faced quest fantasy. A name from our time can carry lots of associations with it, so don’t go calling your dark elf capital city San Diego or putting your ranger hero in lederhosen.
Also, chances are they don’t celebrate Christmas on Planet Mongo.